DESC:FORM 2

THE PATENTS ACT, 1970

(39 of 1970)

&

THE PATENT RULES, 2003

COMPLETE SPECIFICATION

[See Section 10 and Rule 13]

TITLE:

“A SINGLE VANE ROTARY VACUUM PUMP WITH OIL RELIEF GROOVE”

APPLICANT:

PADMINI VNA MECHATRONICS LTD.
A company incorporated under the Indian Companies Act, 1956
having address at
Plot No. 100-101, Sector 35, Phase VII, Udyog Vihar,
Gurgaon-122001, Haryana, India

PREAMBLE TO THE DESCRIPTION:
The following specification particularly describes the invention and the manner in which it is to be performed:

FIELD OF THE INVENTION
The present invention relates to a pump for automobile. More particularly, the present invention relates to a single vane rotary vacuum pump with oil relief groove to achieve reduced pump noise and discharge pressure during exit stroke.

BACKGROUND OF THE INVENTION
A vacuum pump sucks air from brake booster tank and disposes the drawn air along with oil inside the external engine gallery. Thus, a vacuum pump is used to create a vacuum inside the brake booster tank to assists the driver during brake pedal pressing by creating a pressure difference. Further, the multiplied force produced due to the pressure difference is used to press the external master cylinder piston which distributes the pressurized brake oil to all wheels by brake lines and eventually cause the vehicle to stop.
The vacuum pump sucks the air by creating a suction chamber via rotation of vane and sliders assembly which are rotated via the rotor. In conventional vacuum pumps, suction chamber causes air to be sucked from the brake booster tank by a non-return valve (NRV) and with further rotation of the vane creating a positive displacement inside the housing which results in compressing of the sucked air during exit stroke. Thus, a positive pressure is created inside the compression chamber. As the vane comes closest to the exit port, the mixture of air and oil causes increase in the pressure due to change in volume. The increase in pressure causes the mixture of oil and air to pass through the exit port area which further pushes the reed valve to open up and get an escape to the outside of the pump. In this way, the air and oil mixture go out of the vacuum pump housing and the cycle is repeated to create suction chamber and then compression till the exit stroke. Further, a reverse stroke port is also provided in pump housing to prevent the failure of pump during reverse rotation in unfavourable conditions by relieving the filled oil towards outside of pump housing by means of reed valve which covers the port opening area. In a conventional vacuum pump, internal pressure inside the pump increases due to compression of oil and air mixture through vane rotation before the oil discharge from exit port. The vacuum pump mounted on the engine and the rotor rotate directly by coupling, the coupling being connected with the intake cam shaft in engine. The internal pressure of pump at exit stroke generates the impact force on vane sliders colliding with vane slot and pump housing chamber due to clearance between vane sliders and vane or vane sliders and pump housing which creates noise inside the pump. Further, due to uneven fluctuation of sealing reed valve in accordance with increased internal pressure inside the vacuum pump, a worst noise is created in pump when the oil discharges from vacuum pump. Thus, there is a need to solve this problem of reducing noise and reducing internal pressure inside the vacuum pump.
JPH05215089A, discloses about a vacuum pump to prevent the generation of a noise by a fluctuation of discharge pressure when suction pressure reaches the saturated state wherein a vacuum pump has a first suction opening having a check valve and a second suction opening opened and closed by a solenoid valve. When the negative pressure in a vacuum tank is larger than a determined value, the solenoid valve is closed by a pressure switch, and the air in the vacuum tank is sucked through the first suction opening. When the negative pressure in the vacuum tank is smaller than the determined value, the solenoid valve is opened by the pressure switch, and the atmosphere is sucked through the second suction opening. Even when the suction pressure of the first suction opening gets close to the saturated state, thus, the internal pressure in a pump chamber is increased to suppress a fluctuation of discharge pressure, and generation of a noise can be prevented. However, this invention fails to enhance overall engine performance by directing the fluid flow pressure towards suction chamber by reducing the amount of fluid and air mixture to the low-pressure side (suction chamber) of vacuum pump.
US20190271313A1, discloses about a vane pump in which noise can be suppressed. The vane pump including: a housing having a peripheral wall portion, a bottom wall portion, and a pump chamber; a rotor disposed in the pump chamber to be rotatable; a vane disposed to be slidable in the radial direction with respect to the rotor and partitioning the pump chamber into working chambers; and a reed valve that opens and closes a discharge hole of the bottom wall portion. A position at which the sliding direction of the vane with respect to the rotor is inverted from outward in the radial direction to inward is defined as a reference position, and a section of the pump chamber on the discharge hole side with respect to the reference position is defined as a discharge section. A pressure relief groove is disposed in a portion of the bottom wall portion corresponding to the discharge section with a clearance secured between the peripheral wall portion and the pressure relief groove. When the vane overlaps the pressure relief groove, a pair of the working chambers on both sides of the vane in the rotational direction communicate with each other via the pressure relief groove. But this invention fails to reduce the internal pressure peak causing reduction in the impact force on vane slider that makes this invention less efficient. Therefore, there is a need of improvement in the single vane rotary vacuum pump for reducing noise and internal pressure at the time of oil discharge in engine.

OBJECT OF THE INVENTION
The main object of the present invention is to provide a single vane rotary vacuum pump for achieving reduced pump noise and discharge pressure during exit stroke.
Another object of the present invention is to provide a single vane rotary vacuum pump that reduces internal pressure by directing the fluid flow pressure towards suction chamber.
Yet another object of the present invention is to provide a single vane rotary vacuum pump with enhanced suction performance by utilizing an oil relief groove.
Yet another object of the present invention is to provide a single vane rotary vacuum pump that reduces overall noise in the pump and the internal pressure of pump chamber at the time of oil discharge in engine.
Still another object of the present invention is to provide a single vane rotary vacuum pump to reduce the pump noise and the internal pressure of pump chamber by adding oil relief groove on wall of the pump housing chamber.

SUMMARY OF THE INVENTION
The present invention relates to a single vane rotary vacuum pump with oil relief groove to achieve reduced pump noise and discharge pressure during exit stroke by directing the fluid flow pressure towards suction chamber by oil relief groove at pump housing wall to reducing the amount of fluid and air mixture to the low-pressure side (suction chamber) of vacuum pump by utilizing an oil relief groove, resulting in enhancement in the pump overall performance.
In an embodiment, the present invention provides a single vane rotary vacuum pump with oil relief groove comprise of, a pump housing, a locking cap, a non-return valve (NRV), a vane, a reverse exit port, a diaphragm, a slider, an exit port, an o-ring, a big o-ring, a suction chamber, a top cover, a back cover, a compression chamber, a reed valve, a plurality of screws, an oil hole, a reed stopper, a sealing gasket, a screw, a bush, a rotor, a non-return valve screw, a coupling and a housing wall, wherein said single vane rotary vacuum pump includes an oil relief groove that acts as communication media between compression chamber and suction chamber so that the oil and air mixture enter the suction chamber from compression chamber at the time of exit stroke to reduce the pump internal pressure peak with respect of the conventional vacuum pump. This reduction in internal pressure peak cause reduction in the impact force on vane slider at the exit stroke which eliminate the collide noise inside the single vane rotary vacuum pump, additionally the reduction in the internal pressure peak refers to the reduction in pump noise and discharge pressure during exit stroke and the fluid flow pressure is directed towards suction chamber by the oil relief groove at pump housing wall to reducing the amount of fluid and air mixture to the suction chamber of vacuum pump by utilizing an oil relief groove which results in enhancement in the overall performance of the single vane rotary vacuum pump.
The above objects and advantages of the present invention will become apparent from the hereinafter set forth brief description of the drawings, detailed description of the invention, and claims appended herewith.

BRIEF DESCRIPTION OF THE DRAWINGS
An understanding of the single vane rotary vacuum pump with oil relief groove of the present invention may be obtained by reference to the following drawing:
Figure 1 is an exploded view of the conventional vacuum pump according to an embodiment of the present invention.
Figure 2 is a perspective view of the conventional vacuum pump according to an embodiment of the present invention.
Figure 3 is a perspective view of the single vane rotary vacuum pump with oil relief groove according to an embodiment of the present invention.
Figure 4 is another perspective view of the single vane rotary vacuum pump with oil relief groove according to an embodiment of the present invention.
Figure 5 is a schematic perspective view of the single vane rotary vacuum pump with oil relief groove according to an embodiment of the present invention.
Figure 6 is a graphical representation of the internal pressure peak inside the vacuum pump according to an embodiment of the present invention.
Figure 7 is graphical representation of the comparison between pump noise of conventional pump and the single vane rotary vacuum pump with oil relief groove.

DETAILED DESCRIPTION OF THE INVENTION
The present invention will now be described hereinafter with reference to the accompanying drawings in which a preferred embodiment of the invention is shown. This invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiment set forth herein. Rather, the embodiment is provided so that this disclosure will be thorough, and will fully convey the scope of the invention to those skilled in the art.
Many aspects of the invention can be better understood with references made to the drawings below. The components in the drawings are not necessarily drawn to scale. Instead, emphasis is placed upon clearly illustrating the components of the present invention. Moreover, like reference numerals designate corresponding parts through the several views in the drawings. Before explaining at least one embodiment of the invention, it is to be understood that the embodiments of the invention are not limited in their application to the details of construction and to the arrangement of the components set forth in the following description or illustrated in the drawings. The embodiments of the invention are capable of being practiced and carried out in various ways. In addition, the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting.
The present invention is directed towards a single vane rotary vacuum pump with oil relief groove in which there is a reduction in pump noise and discharge pressure during exit stroke that also results in enhancement of overall performance of the single vane rotary vacuum pump.
In an embodiment, the present invention provides a single vane rotary vacuum pump with oil relief groove comprise of, a pump housing, a locking cap, a non-return valve (NRV), a vane, a reverse exit port, a diaphragm, a slider, an exit port, an o-ring, a big o-ring, a suction chamber, a top cover, a back cover, a compression chamber, a reed valve, a plurality of screws, an oil hole, a reed stopper, a sealing gasket, a screw, a bush, a rotor, a non-return valve screw, a coupling and a housing wall, wherein said single vane rotary vacuum pump includes an oil relief groove that acts as communication media between compression chamber and suction chamber so that the oil and air mixture enter the suction chamber from compression chamber at the time of exit stroke to reduce the pump internal pressure peak with respect of the conventional vacuum pump. This reduction in internal pressure peak cause reduction in the impact force on vane slider at the exit stroke which eliminate the collide noise inside the single vane rotary vacuum pump, additionally the reduction in the internal pressure peak refers to the reduction in pump noise and discharge pressure during exit stroke and the fluid flow pressure is directed towards suction chamber by the oil relief groove at pump housing wall to reducing the amount of fluid and air mixture to the suction chamber of vacuum pump by utilizing an oil relief groove which results in enhancement in the overall performance of the single vane rotary vacuum pump.
Referring to Figure 1, an exploded view of the conventional vacuum pump is depicted. The conventional vacuum pump (100’) depicted in Figure 1 is mounted over the sides of engine block and driven by the engine cam shaft (not shown in drawing) sealed with a sealing gasket (17), further which is coupled with a mechanical coupling (10) and a locking cap (11) along with a rotor (9) which rotates an assembly of vane (12) and a plurality of sliders (13A), (13B) inside a pump housing (1). The cam shaft rotates the vacuum pump rotor (9) and engine oil for lubrication enters the vacuum pump housing (1) via oil hole (26) and internal clearances between parts at certain pressure which is maintained by external engine’s oil pump. Hence oil insides the vacuum pump causes the lubrications of all rotating parts which results in decrease of friction force. The vacuum pump has a non-return valve (NRV) (2) composed of a top cover (5), diaphragm (3) and NRV o-ring (4) which relates to the external brake booster via an external hose pipe. The pump housing (1) is enclosed by a big o-ring (14), a back cover (15) and a plurality of screws (16) to maintain good sealing inside the pump housing (1). The vacuum pump sucks the air from the booster tank and disposes it along with oil inside the external engine gallery. Therefore, a certain vacuum is achieved inside the brake booster tank which assists the driver during brake pedal pressing by creating a pressure difference inside it. Further, the multiplied force is used to press the external master cylinder piston which distributes the pressurized brake oil to all wheels by brake lines and eventually causes the vehicle to stop.
The conventional vacuum pump (100’) as depicted in Figure 1 sucks that air by creating a suction chamber (24) via rotation of vane (12) and sliders (13) assembly which are rotated via the rotor (9). The suction chamber (24) causes the suction of air from the brake booster by non-return valve (NRV) (2) and with further rotation of the vane (12); it creates a positive displacement inside the housing (1). Further it results the compressing of the sucked air during its exit stroke which causes creation of positive pressure inside the compression chamber (25). Therefore, as the vane (12) comes closest to the exit port (23), the mixture of air and oil causes the increase in the pressure due to change in volume. This increase in pressure causes the mixture of oil and air to pass through the exit port area (23) which further pushes the reed valve (6) to open up and get an escape to the outside of the pump. In this way the air and oil mixture go out of the vacuum pump housing (1) and cycles repeats itself to create suction chamber (24) again and then again compression till the exit stroke. Further a reverse stroke port (22) is also provided in pump housing (1) to prevent the failure of pump during reverse rotation in unfavourable conditions by relieving the filled oil towards outside of pump housing (1) by mean of reed valve (6) which covers the port opening area.
Referring to Figure 2, a perspective view of the conventional vacuum pump is depicted, wherein, the oil and air mixture enter the exit passage area (23) from the compression chamber (25). The internal pressure inside the pump increases due to compression of oil and air mixture through the vane (12) rotation before the oil discharge from the exit port (23). This oil discharge in engine through lifting of reed valve (6) and the vacuum pump oil pressure discharge cycle repeat two times in one complete rotation. So, oil discharge pressure peak discharge in pump got two times peak in one vacuum pump rotation. The conventional vacuum pump (100’) is mounted on engine and rotor (9) rotate directly by the coupling (10), the coupling (10) is connected with the intake cam shaft in engine. The internal pressure of pump at exit stroke generates the impact force on the vane sliders (13A), (13B) and vane sliders (13A), (13B) collides with vane slot (12) and the pump housing (1) chamber due to clearance between vane sliders (13A), (13B) and vane slot (12) or vane sliders (13A), (13B) and pump housing (1) which create the noise inside the pump. The reed valve (6) opens abruptly. The reed valve (6) opening operation is repeated cyclically in accordance with fluctuations in internal pressure of the pump chamber. Due to uneven fluctuation of sealing reed valve (6) in accordance with internal pressure increased inside the vacuum pump and create the worst noise in pump when the oil discharge from vacuum pump.
Referring to Figure 3, a perspective view of the single vane rotary vacuum pump with oil relief groove is depicted. The single vane rotary vacuum pump (100) incorporated an oil relief groove (21) on a pump housing wall (20) at an exit port (23) side of single vane rotary vacuum pump (100). The oil relief groove (21) acts as a communication between the compression side (25) and suction chamber (24) so that the oil and air mixture enter the suction chamber (24) from compression chamber (25) at the time of exit stroke to reduce the pump internal pressure peak with respect of conventional vacuum pump (100’). This reduction in internal pressure peak cause reduction in the impact force on vane slider (13A) and (13B) at the exit stroke which eliminate the collide noise inside the vacuum pump as depicted in Figure 4 and Figure 5.
EXAMPLE 1
Experimentation Analysis
The noise and internal pressure of the conventional vacuum pump (100’) are measured without oil relief groove (21) and then the noise and internal pressure of the single vane rotary vacuum pump (100) is measured with oil relief groove (21) under same testing conditions to get the precise comparable results. The testing conditions are a) suction performance test- (vacuum achieving time), b) pump speed: engine idle rpm to maximum rpm, c) rotation: clockwise & counterclockwise when viewing from cover side, d) oil temperature: as per engine running condition, e) oil pressure: as per engine running condition, f) lubricating oil: engine oil, g) ambient pressure: vacuum as per engine requirement, h) vacuum tank volume: as per vehicle brake booster volume.
The results obtained from this experimentation are depicted in Figure 6 and Figure 7. Figure 6 depicts that the internal pressure peak inside the vacuum pump has been reduced 20-25 % from the conventional pump after adding the oil relief groove (21) at pump housing wall (20). From Figure 7, it has been observed that with adding the oil relief groove (21) at pump housing wall (20) inside the pump noise is reduced 10-12% as compared to the conventional pump (100’).
Therefore, the present invention provides a single vane rotary vacuum pump with oil relief groove in which there is a reduction in pump noise and discharge pressure during exit stroke that also results in enhancement of overall performance of the single vane rotary vacuum pump.
Many modifications and other embodiments of the invention set forth herein will readily occur to one skilled in the art to which the invention pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the invention is not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.
The foregoing description of embodiments of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and modifications and variations are possible in light of the above teachings or may be acquired from practice of the invention. The embodiments were chosen and described in order to explain the principals of the invention and its practical application to enable one skilled in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated.
8 ,CLAIMS:CLAIMS
We claim:
1. A single vane rotary vacuum pump (100) with oil relief groove, comprising of:
a pump housing (1);
a vane (12);
a reverse exit port;
a slider (13);
an exit port (23);
a suction chamber (24);
a compression chamber (25); and
an oil hole (26);
wherein:
said single vane rotary vacuum pump (100) includes an oil relief groove (21) that acts as a communication media between the compression chamber (25) and said suction chamber (24), so that a mixture of oil and air that enters said suction chamber (24) from said compression chamber (25) at the time of an exit stroke, which results in reduction in an internal pressure peak of said single vane rotary vacuum pump (100) that causes a reduction in the impact force on a vane slider (13A) at the exit stroke that reduces the collide noise inside the single vane rotary vacuum pump (100).
2. The single vane rotary vacuum pump (100) with oil relief groove as claimed in claim 1, wherein said single vane rotary vacuum pump (100) comprises of a locking cap (11), a non-return valve (NRV) (2), a diaphragm (3), an o-ring (4) and a big o-ring (14), a top cover (5), a back cover (15), a reed valve (6), a plurality of screws (16), a reed stopper, a sealing gasket (17), a screw, a bush, a rotor (9), a non-return valve screw, a coupling (10) and a housing wall (20).
3. The single vane rotary vacuum pump (100) with oil relief groove as claimed in claim 1, wherein said reduction in the internal pressure peak refers to the reduction in pump noise and discharge pressure during exit stroke.
4. The single vane rotary vacuum pump (100) with oil relief groove as claimed in claim 1, wherein said oil relief groove (21) directs a flow pressure of said mixture towards the suction chamber (24) for reducing an amount of said mixture which results in enhancement in the overall performance of the single vane rotary vacuum pump (100).
5. The single vane rotary vacuum pump (100) with oil relief groove as claimed in claim 1, wherein said reduction in internal pressure peak ranges from 20 to 25%.
6. The single vane rotary vacuum pump (100) with oil relief groove as claimed in claim 1, wherein said collide noise is reduced from range 10 to 12%.